Magneto



Sept. 6, 1927. 1,641,384

. H. W. HENRY MAGNETO Filed Nov. 5, 1923 2 Sheets-Sheet 1 VM-JMJ W. I

6 192 Sept 7 H. w. HENRY H MAGNETO Filed Nov. 5 1923 2 Sheets-Sheet 2 k W h 7v 1 k w $4M :i :2? t: E

Patented Sept. 6, 1927.

UNITED STATES 1,641,384 PATENT OFFICE.

HOWARD W. HENRY, OF NEWARK, NEW JERSEY, ASSIGNOR TO GENERAL MOTORS RE- SEARCH CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE.

MAGNETO.

Application filed November 5, 1923. Serial No. 672,735.

This invention relates to magnetos having a rotating permanent magnet and includes among its objects the advancing and retarding of the spark timing in response to variations in speed.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawings;

Fig. 1 is a side view partly in section of a magneto including the present invention.

Fig.- 2 is a sectional view on a reduced scale taken on the line 22 of Fig. 1.

Fig. '3 is a sectional view on the line 3-3 of Fig. 1, showing the relation of the magneto shaft, the permanent magnet and the speed responsive mechanism in normal condition'. I

Fig. 4 is a view similar to Fig. 3 but showing the relation of the magneto shaft, the permanent magnet and the speed responsive device in position for advancing the timing of the spark.

Fig. 5 is a plan View of the timer included in the timer distributor unit operated by the magneto shaft. v

Referring to the drawings, in which 'is shown a type of rotating permanent magnet such as disclosed in the copending application of J ohn H. Hunt, Serial No. 670,616 filed October 24, 1923, the magneto frame of nonmagnetic material is designated by numeral 20 and includes a supporting flange 21, a hub 22 and a magnet housing 23. As shown the flange 21 isconnected with the housing 23 by the hub 22 and stiffening ribs 24. By means of bolts not shown the-flange 21 may be attached to an engine frame and provide a closure for'an opening through which the magneto operating mechanism may extend. A cover member 25 is attached by screws 26 to the magnet field housing 23. The cover member 25 includes two stationary laminated armature poles 27 and 28 aboutwhich is cast non-magnetic metal to form a cup-shaped member, portions of the side walls of which are provided by the armature pole pieces 27 and 28. Between said pole pieces 27 and 28, the top wall of the cover member 25 as viewed in Fig. 3 is provided with an opening 29. The magneto armature 30 includes a core 31 surrounded by primary and secondary windings located within the casing 32 which is supported by the core 31. The core 31 is attached to the armature poles 27 and 28 by screws 33 entering holes 34 and 35 tapped into the poles 27 and 28. For further description of the construction of the magneto armature, reference is made to the copending application of John H. Hunt referred to. The magnet frame hub 22 and the cover 25 provide bearings 34 and 35 respectively which support the journals 36 and 37 respectively of magneto shaft 38. Shaft 38 includes a portion 39 for receiving a thrust washer 40 and a portion 41 to which is at tached a driving gear 42 by means of a key' 43 and a nut 44. r is a permanent magnet having poles 51 provided with laminated pole pieces 52 attached in any suitable manner such as by placing the laminated pole pieces in a mould and casting the magnet metal so that, when cold, the magnet poles will be permanently attached to the laminated pole pieces. The magnet includes a yoke 53 provided with a hub 54. The yoke and hub are bored to receive the portion 36 of shaft 38. The hub 54 provides a journal for the magnet which is received by a bearing 55 provided in the hub 22. Within the bearing 55 the journal 54 is provided with a spiral gear 56 and a thrust washer 57 is located between the gear 56 and the end of bearing 34. The passages 58 and 59 are oil ducts leading to and from the bearings 34 and 55, and the gear 56. The right handend, as viewed in Fig. 1, of the magnet 50 is supported from the shaft 38 by means of a non-magnetic disk60 provided with a hole through which the shaft portion 37 may extend. Disk 60 is attached to the magnet pole 51 by means of'screws 61.

The magnet 50 is not directly attached to the magneto shaft 38 but is driven by the .shaft through the agency of means responsive to speed for varying the angular rela- 100 ment is provided with a tail member 7 pro-' 110 The plates 72 are identical andprovide vided with a rocking camming surface, 78. These tail members 77 are maintained in engagement with the magnet poles 51 by means of two springs 79. Each spring 79 has end 80 bearing against a pole piece 51, and intermediate portion 81 looped around the shaft 38 and an end portion 82 engaging the plate 72, said portion 82 being received within one ofthe series of notches 83 pro-' vided in an arcuate flanged member 84 extending from the plate 72. As viewed in Fig. 3 if the end 82 of the spring 79 is moved clockwise from its position and laced in one of the notches 83, the tension 1n the spring will be increased. In this manner the spring can be adjusted to suit the requirements of the apparatus.

The hub 22 of the magneto frame is provided with a tubular extension: for receiving the tubular shank 91 of the timer cup 92 included in a timer distributor .unit 93 which also includes a distributor 94. The shank 91 provides a bearing for timer shaft 95 to which is attached a gear 96 meshing gear 56. Rotation of the shank 91 is prevented by means of a set screw 97. Adja' cent its upper end, the shaft 95 drives a distributing apparatus, and a timer cam 100 for intermittently separating a pair of contacts 101 and-102 connected with the ignition primary circuit. The contact 102 is attached to a movable breaker lever 103 pivoted at 104 upon the timer cup 92. A spring 105 causes the contacts to be closed or the cam follower 106 yieldingly to engage the cam 100 when said cam separates I said contact.

The operation of the invention is as follows:

The rotation of the magnet produces a1- ternations of flux in the armature magnetic circuit producing an alternating current in the primary ignition circuit. At the peaks of the primary current waves the primary circuit is broken by separating the timercontacts thereby inducing sparking impulses in the secondary windings of the magneto. It is apparent that if the magnet be advanced with respect to the magnetshaft then the causing the magnet poles 51 to be rotated y o the spirit and scope of the invention. fame of the peaks of the alternating current waves will be advanced' If the time of counterclockwise relative to the shaft 71. Since the fulcrum points 73 and 74 are moved away from their adjacent magnet poles 51 it is apparent that the springs 79 will be wound up. In this manner the springs exert a force tending tov restrain outward movement of the weights 75 and 7 0 and cause the weights to move inwardly as shown in Fig. 3 when the speed decreases to c a certain amount. Direction of rotation of shaft 71 is indicated by arrow 110 in Figs. 3 and 4 and arrow 111 in Fig. 2 and 112 in Fig. 1. his apparent that the tail portions 77v of the weights 78 and 77 rock upon the plane surfaces of the. magnet poles 51 in order to vary the angular relation of the magnet and its shaft.

The advancing of the magnet relative to its shaft produces an advancing of the gear 56 and consequently of the gear 96 and the cam 100. The direction of rotation of the gear 56 is indicated by the'arrow 111 in Fig. 2 and the direction of rotation ofthe cam is indicated by arrow 114 in Fig. 5. It is therefore apparent that if the magnet be advanced relative to its shaft, the cam 100 will be advanced in a counterclockwise direction as viewed in Fig. 5. In this manner the advancing relative to the magneto shaft of the instant of the peak in the alternating current wave and of the'separation of the timer contacts will be effected by means which does not change the relation of the instant of contact separation to the instant of the current peak.

It is apparent also that the speed responsivedevice is exceedingly compact in con- 'struction and can be housed between the magnet poles. As this device occupies space usually left vacant, no housing additional space is required.

While the form of mechanism herein shown and deseribed constitutes a preferred embodiment of one form of invention, it is to be understood that other forms might be adopted and various changes and alterations made in the shape, size, and proportion of the elements therein without departing from What is claimed is as follows: 1. A magneto comprising, in combination, arotary magnet provided with poles and a connecting yoke, a drive shaft extending through the yoke and between said poles, and speed responsive means located bet-ween said poles drivingly connecting said shaft. and magnet for advancing or retarding said magnet relative to the drive shaft accord ing to the speed of rotation. I

2. A magneto comprising, in combination, a permanent magnet including parallel pole portions, and a connecting yoke provided with an aperture, a drive shaft extending through said apertured yoke and mounted for rotation with its axis parallel to said pole portions, means for mounting the magnet for rotation about the axis of said shaft,

and speed responsive means drivingly connecting the magnet and shaft located between said pole portions for advancing or retarding said magnet relative to the drive shaft according to the speed of rotation.

3. A magneto comprising, in combination, a rotary permanent magnet, a stationary ar-. mature including an ignition coil having primary and secondary windings, an ignition timer including a timer cam and contacts intermittently separated by said cam to-make and break said primary Winding, an

operating shaft, positive gearng connecting the rotary magnet and timer cam, and sp ed responsive means drivingly connecting the operating shaft with the magnet for advancing or retarding said magnet relative to the drive shaft.

4. A magneto comprising, in combination, a rotatably supported permanent magnet including parallel pole" portions and a connecting yoke portion, a drive shaft, speed responsive means drivingly' connecting the drive shaft to the maget, an ignition timer incl'udng a timer shaft, and positive gearing for connecting the timer shaft with the magnet including a' gear fixed to the magnet yoke.

In testimony whereof I hereto afiix my signature.

HOWARD W. HENRY. 

